1. Field
The present disclosure relates to a spool valve.
2. Description of the Related Art
Spool valves have configurations in which spools are slidably placed in spool holes of valve housings. Such spool valves have often been used for various applications including pressure control valves and flow rate control valves. Such a known spool valve includes a valve housing having a substantially cylindrical spool hole, a spool placed in the spool hole and having a substantially cylindrical columnar shape, and a spring for biasing the spool in the spool hole. The spring is located at an end of the spool in the spool hole, and biases the spool toward the other end along an axial direction. The valve housing has an oil passage having a plurality of ports that are open at the inner peripheral surface of the spool hole. The ports of the oil passage communicate with oil grooves formed in the outer peripheral surface of the spool. The valve housing has a control pressure supply passage through which a control hydraulic pressure for operating the spool is supplied.
The spool valve as described above supplies the control hydraulic pressure through the control pressure supply passage, and thereby, performs control such that the Spool slides toward the end facing the spring against a biasing force of the spring. In this manner, a communication state between the ports open to the spool hole and the oil grooves in the spool is switched, and the distribution path in the oil passage is controllably switched. Japanese Unexamined Patent Application Publication No. 2002-206651 is an example of related art.